Partial Encapsulation for Multi-Chip Package Testing
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Solution Overview
Problem
Conventional encapsulation processes for multi-chip semiconductor devices restrict the type and depth of testing that can be performed, as components are fully encapsulated, limiting reliability and durability, especially in harsh environments like tire pressure monitoring systems.
Innovation Solution
A partial encapsulation method that leaves landing pads on the leadframe non-encapsulated, allowing for pre-testing of integrated circuits and surface mount components before full assembly, using a mold-transfer process with plastic or ceramic materials to form a well structure for subsequent encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional full encapsulation process is used, then manufacturing efficiency is improved, but testing capability and reliability are restricted
Solution Approach 1:
The encapsulation process is divided into two distinct stages: first, a partial encapsulation is performed allowing access to landing pads for testing and component attachment; second, a full encapsulation is performed after testing is complete. This segmentation enables both manufacturing efficiency and testing capability to be achieved at different stages of the process.
Solution Approach 2:
Testing and calibration of integrated circuits and attachment of surface mount components are performed before the final full encapsulation. This preliminary action ensures that all components are verified and properly attached while the landing pads are still accessible, thereby ensuring reliability before the device is permanently sealed.
2Strength
If full encapsulation is performed early, then device protection is improved, but component reworking capability is lost
Solution Approach 1:
The encapsulation is segmented into a first encapsulation material that provides partial protection while maintaining access to landing pads, and a second encapsulation material that provides full protection after testing. This allows device protection to be progressively improved without permanently losing reworking capability.
Solution Approach 2:
The degree of encapsulation and protection is made dynamic rather than static. The device transitions from a partially encapsulated state (allowing reworking) to a fully encapsulated state (providing maximum protection) based on the completion of testing and calibration, optimizing both protection and reworking capability at different stages.
3Device complexity
If landing pads are fully encapsulated, then manufacturing simplicity is improved, but testing and calibration capability is restricted
Solution Approach 1:
The manufacturing process is segmented into distinct phases: first, attach surface mount components to exposed landing pads and perform testing; second, perform full encapsulation. This segmentation adds a process step but enables comprehensive testing and calibration, improving measurement precision without significantly complicating the overall manufacturing approach.
Solution Approach 2:
All testing, calibration, and component attachment operations are performed as preliminary actions before the final full encapsulation. This ensures that landing pads remain accessible during critical verification stages, maintaining measurement precision while ultimately achieving a simple fully-encapsulated final product.
Data Source
AI summary
Subject matter disclosed herein may relate to packaging for multi-chip semiconductor devices as may be used, for example, in tire pressure monitoring systems.